Tree peonies differ from bush peonies in that their woody stems do not die down to the ground in winter. Derived from the Chinese moutan peony more than 1400 years ago, they usually grow to 5’ tall, so are more accurately classified as shrubs than trees. They bloom from April to May, live a long time, and get better with age. Plant them in the fall in partial shade, prune them only occasionally if needed and remove the suckers that grow from the roots.  ‘Kinkaku’ has huge, deep-yellow blossoms that can be up to 8” or more across.